Commonly available products (such as chicken pieces, ground beef) as well as other foods (such as lettuce, sprouts) frequently carry bacterial pathogens such as E. coli and Salmonella sp. Contamination of chicken carcasses by Salmonella sp. during processing is a particularly common problem. The Salmonella sp. frequently originate as common constituents of the digesta in the lower GI tract of the birds. The bacteria can cause sickness when the product is consumed without adequate washing or cooking.
Methods used to destroy or reduce bacterial contamination other than washing or cooking typically involves the use of ultraviolet radiation or gamma sterilization. Additionally, even freezing frequently does not decrease the level of bacterial contamination. Decontamination is therefore not typically practical under ordinary conditions, and the food can be recontaminated shortly after sterilization.
Current methods for preventing food poisoning are therefore chiefly based on maintenance of good hygiene during food processing. Break downs in sanitation procedures have frequently resulted in sale of food products containing pathogenic bacteria with subsequent infection of consumers.